Maybe Towerhobbies still IS the cheapest to buy, because "we" (international customers) get pretty huge discounts. Like: 75$ off 300$. So I can get a MMM Combo for 225 dollar :D
Yes, those HK do this, on hobbycity you can even choose which amount they should put on it. Last time I chose for 30%
1. Buy your stuff from Rc-M. He won't mark as gift, but packages go through customs easily and shipping is fast.
2. Buy your MMM combo from a chop-shop off ebay. Prices are still pretty high, but these packages get by customs pretty easy and sellers will sooner label the package as gift.
3. Liquidrc packages tend to pass customs easily aswell. Prices will be higher, but you'll save on customs.
4. Buy in batches. Don't make one big order, but make a few small ones. Again more shipping costs, but easier to pass customs.
5. Buy in Europe (UK), some shops actually have pretty good prices.